Threaded fasteners are used in many applications and are available in several thread forms. The several thread forms in use can require rapid determination of component thread acceptability of individual fastener components in production activities.
Proper performance and extended service life of the several components of a product requires the connections between the components be strong, durable and tight. It is therefore important that the ready verifiable classification of available threaded forms be available as to threaded forms of fasteners components. A ready to use thread checker of nuts and bolts that is conveniently available can be a useful tool. The present invitation provides a wall mounted thread checker of standard and metric thread sizes in conjunction with a separate set of gauges which serve as a method to verify the gauge results of the wall-mounted thread checker.
A number of different dimensions pertaining to thread sizes are of critical importance. Standards as to dimension have been determined for thread values including thread lead, thread height, thread angle, thread taper, and pitch diameter. The quality of individual fasteners may be assessed though comparing the thread characteristics of a fastener to maximum and minimum levels of acceptance. However, the degree to which quality of a fastener may be determined frequently depends on the time required to make the assessment. One minute may be required to accurately gauge a fastener's dimensions. Conventionally it may be necessary to make trade offs between quality control and production speed, thereby using fewer measurements then would be advantageous for full quality assurance. The instant invention provides a means complying with a lessened standard of quality assurance but meets specified standards as to dimensions reality checked.
A number of gauge systems have been developed for measuring the inside and outside of threaded fasteners surfaces. In the gas and oil production industry, the American Petroleum Institute (API) has adopted specifications for threading, gauging and thread inspection of components used in the industry. In specifying the standard dimensions for the various thread parameters, the API specifications provide a procedure for checking the accuracy of actual thread measurements and parameters as compared with design dimensions. The procedure, which is accepted and used by the Petroleum Industry utilizes a series of ring and plug gauges to check the accuracy of the actual threads against the API standard thread for the particular thread configuration and threaded product.
The ring and plug gauge system is known as a “go and not go” gauge system. The plug gauge as a gauge device usually has a double end, having a “go” end and a “not” go end. When the tested piece is of the correct size, one of the gauges will slip into the test article and the other end will not. A ring gauge is a standard cylindrical gauge (male and female). The ring or external gauge is a bored ring and is made in both a “go” and “not go” dimension.
Ring and plug gauges systems have a certain inherent shortcoming. Rings and plugs do not directly measure the individual thread parameters such as pitch diameter. Ring and plug gauges can measure only the functional fit of the threads. Also ring and plug gauges can measure accurately only perfectly formed threads.
Despite these shortcomings, ring and plug gauges comprise the only API approved gauging system for measuring the functional fit of the tapered threads.
Indicating thread gauges are available for proving a direct read out of the thread parameter being measured. U.S. Pat. Nos. 3,859,730, 4,672,750, 5,048,197, 6,055,329, 6,111,601; and 7,343,034 disclose and teach tools and apparatus for thread measurement and qualifying fastener devices. Typically, these devices utilize tools and procedures not adapted for ready evaluation of fastener threads on the bases of go and not go dimensions.
Additionally, the core methods of use and maintenance of thread plug gauges and cylindrical contain ring gauges require that the gauge user provides a certain minimum level of care to insure accurate and clean gauges.
The thread plug gauges and cylindrical ring gauges are manufactured to precise tolerances. Typically the gauge surfaces have a clear finish and are made to ANSI standards for gauges for both plug and ring gauges. Because heat, moisture, abrasions, metal chips, dirt, and oil can impair accurate reading, core standards are frequently used for test gauges to protect and prolong the useful life of the individual plug and ring gauges.
For example, manufacturers of plug and ring gauges recommend that:
                1) Soft clean individual clothes be used to keep the individual gauges free from contact with dirt of oil for long periods of time. Oils containing dirt can damage the polished surface of the plug or ring gauge.        2) A soft non-abrasive clean cloth is recommended be used to wipe each gauge clean before and after each use.        3) The gauges are best stored in a dry and cool atmosphere, away from sunlight or any intense heat.        
The presence of heat can cause the gauges to expand and then contract when cool, to provide incorrect measurements when so used.                4) Inspection gauges be kept away from operators using inspection gauges to check work in progress, operations may force the inspection gauges into or over the work piece to quickly damage the precise tolerances.        
The methods of use and of maintenance of plug and ring gauges accordantly are of significance in the wear life and performance required of the gauges, and are provided by the display structure of the instant invention.
In the prior art, a number of devices and procedures are used for measuring threads. U.S. Pat. No. 2,822,624 teaches a three-wire method for measuring threads using a wire holder to hold the gauging wires used in the three wire method to eliminate the difficulty of handling the three wires.
U.S. Pat. No. 3,218,724 teaches and claims a thread gauge unit comprising two gauge plates. The first gauge plate carries a plurality of gauging studs of different thread size and diameter and others of different thread size and the same diameter. The second gauge plate also contains a plurality of threaded opening, each opening receiving in threaded engagement therewith a gauging stud of a corresponding thread size and diameter of the first gauge plate. Identifying indicia indicating the thread size and diameter of each gauging stud are marked on the surfaces of the first gauge plate and on both surfaces of the second gauge plate of each threaded opening. In use, the threaded studs of the first gauge plate form a gauging element for gauging the threads of an applied nut. Meshing of the threads of a bolt or screw against the threads of a stud indicates the thread size of the screw or bolt. Selection of the proper threaded opening in the second gauge plate will indicate the thread size of the inserted screw or both. The two gauge plates are secured together by threaded engagement of the first plate studs with corresponding threaded openings in the second plate for transport or storage. However, such an arrangement for storage and transport hinders the ready accessibility of the two gauge plates for use of measuring threads of separate screws and or bolts.
U.S. Pat. No. 5,182,862 teaches and claims and indicating thread gauge wherein thread form elements engage its threaded product while an indicator transduces radial displacement of the thread form elements. The thread form elements engage the thread form of the threaded product. A thread form element can be a thread role or thread segment that can rotate the thread form element to engage the thread form of the threaded product. The indicating thread gauge device is cumbersome and not suitable for ready evaluation of small handable screw thread bolts and crew thread nuts.
U.S. Pat. No. 4,611,404 teaches and claims a caliper for thread measurement where the caliper has a body of at least two cooperating members having a combination structure attached to each member and having a contour of the object being measured by the caliper. Application of the contour to the object being measured permits measurement of the threads of the objects being measured and is particularly useful in measuring thread diameters on large pieces of equipment.
U.S. Pat. No. 7,343,685 discloses and claims a thread verification and checking apparatus and methods for threaded bores in small plastic parts in which a threaded top is mounted to rotate on a fixed access at a workstation. The parts' threaded bore is verified and verified, at which point the part engages a reversing limit to drive the verified part back of the top.
It is the object this invention to provide a thread gauging device to enable the ready ascertaining of the size of the thread of a bolt or shaft as well as the size of the thread of a nut.
It is also the principal object of this invention to provide a means of ready access to plug gauges mounted on a support display structure as a device, which readily identifies the thread size wherein the precision tolerances standards of the plug gauges are not impaired by the presence of metal chips, dirt and surface oil containing dirt.
It is also an object of this invention to provide mounted displayed ring gauges to be easily available for checking thread sizes of cylindrical objects and nuts wherein the precision tolerance standards of the ring gauges are not impaired by the presence of metal chips, dirt, and surface oil containing dirt.
It is also an object of this invention to provide a ready means of identifying thread sizes of cylindrical objects such as shafts and bolts and interior thread sizes of bore holes wherein the test object can be brought to the ring or plug gauge mounted upon a support surface.
It is also an object of this invention to provide a separate series of ring gauges on the bore interior surfaces of the mounted plug gauges of both the standard and metric plug gauges. The interiors of the plug gauges are bored to precision standards to provide separate means of measuring thread sizes of bolts and other cylindrical objects.
As a separate means of checking the threat of nuts and bolts checked by means of the wall mounted thread checker, the plug and ring gauges mounted upon the support structures are separately assembled as individual units upon a wire lanyard. The individual gauges comprise a combined plug gauge and a ring gauge in each embodiment. Each embodiment comprises a plug gauge with a threaded projecting end which is used to check internal thread and a second end which has an interior threaded diameter which is used to check the threaded surface of a bolt or cylindrical object.
The thread identifying numbers of the individual gauges embodied as separate plug and ring gauges match the thread identifying numbers of the individual plug and ring gauges mounted upon the thread checker structure as a plug in ring gauge support unit. The separate embodiments of the plug and ring gauges mounted upon the gauge support unit permit the user to verify the thread dimensions of threaded objects not conveniently measured by plug and ring gauges mounted upon the support structure.